Dear Tobi
Some functions in ACCPAC require exclusive access to the data (i.e. posting transactions is one of these). Due to this, other programs trying to access data while these functions are 'in progress' may give unexpected behaviour or results, or just deny access while that process is active.
Because QR must access data in order to provide the information required in the report, it is possible that the numbers are incorrect during times in which these types of operations are being performed by other Users.
Apart from this, there is no problem with printing reports while other Users are in ACCPAC, however this depends entirely on the type of report being printed and of course, what process is being run in ACCPAC at the time.
You may have to schedule the printing of these types of reports at a time of day that is not as busy.
P.S. The version of QR you are using is discontinued. The current shipping version is 6.5A (001213).
Regards,